| ??? 03/07/06 13:48 Modified: 03/07/06 14:02 Read: times |
#111508 - 40MHz bus speed Responding to: ???'s previous message |
I was at Intel's site today and checked also FLASH - of course, where else than at the "mother of all FLASH"es? They seem to have some "embedded flash" in TSOP (although 56-pin).
Product brief said:
• Fast 85 ns asynchronous access time
• Burst read mode support at 40 MHz for fast code execution It seems to me it tries to say, under certain conditions the access time is 25ns? It is certainly not the solution for Richard, but perhaps leaves a couple of question marks behind... Jan Waclawek [added lated] So this day is not wasted, I learned something new today: the modern FLASH to fulfill the high speed access requirements, work in a slightly similar way than SDRAM: as the physical access to the memory cells is slow (~70-120ns), they internally read a big chunk of memory in parallel, buffer it and are able to provide such a "page" (or data in "burst") significantly faster (~20-30ns). Of course, the mcu must be aware of this and be able to wait until the memory fetches a new page, if necessary. A good source of info is the Spansion (a quick lookup in my chart -> yes, AMD's & Fujitsu's FLASH business merged a while ago :-) website: http://www.spansion.com/support/t...notes.html especially http://www.spansion.com/applicati.../23710.pdf http://www.spansion.com/applicati.../23711.pdf Maybe not terribly relevant to '51, but nevertheless good to know. JW |
